The invention relates to uses of an extract of the plant Terminalia catappa in the cosmetic and pharmaceutical fields, especially the dermatological field.
It relates more precisely to uses of an extract of this plant as a cosmetic agent.
The plant Terminalia catappa belongs to the Combretaceae family, which is found particularly in New Caledonia.
The systematic experiments carried out by the inventors have made it possible to demonstrate a number of surprising enzymatic actions of the extracts of this plant, particularly inhibitory actions on several enzymes, especially phospholipase A2, 5xe2x80x2-lipoxygenase, tyrosinase and 3 xe2x80x2,5xe2x80x2-cAMP phosphodiesterase, which has made it possible to consider its use in cosmetic and pharmaceutical products, especially dermatological products.
Phospholipase A2 (PLA2) is an enzyme produced by membrane cells. It predominates in cells associated with inflammation phenomena, such as mastocytes. Through its action it releases the arachidonic acid bound to the membrane phospholipids. This acid then metabolizes to different lipidic mediators of inflammation and allergy, such as leukotrienes and prostaglandins.
Like PLA2, 5xe2x80x2-lipoxygenase, hereafter called xe2x80x9clipoxygenasexe2x80x9d , is a membrane enzyme. It is involved in the xe2x80x9cinflammation cascadexe2x80x9d downstream of the release of arachidonic acid by PLA2, converting this acid to leukotrienes, which are mediators of inflammation.
3xe2x80x2,5xe2x80x2-cAMP phosphodiesterase, hereafter called xe2x80x9cphosphodiesterasexe2x80x9d or xe2x80x9cPDExe2x80x9d, is the enzyme which converts cAMPxe2x80x94a second messenger involved in controlling the cell metabolismxe2x80x94to inactive AMP. Consequently, the inhibition of PDE by an inhibitor makes it possible to maintain a high intracellular level of cAMP, which has the effect especially of activating the protein kinases A and, via this process, makes it possible to promote lipid degradation.
Furthermore, it is also known that cAMP plays a part in counteracting certain inflammatory processes (M. Hitchcock, J. Immunol. (1977) 188 557). Also, it has been described that phosphodiesterase increases with age (S. K. Puri and L. Volicer, Mechanisms of Aging and Dev. (1981) 15 239). The inhibition of phosphodiesterase will therefore make a contribution to combating the effects of ageing, particularly on the skin.
Tyrosinase is the key enzyme in the synthesis of melanin and hence in the metabolism of skin pigmentation. In cosmetics, the inhibition of tyrosinase by appropriate agents has applications in the local treatment of skin hyperpigmentations such as liver spots.
Thus it has been demonstrated by the inventors that, by virtue of their inhibitory action on the above-mentioned enzymes, extracts of the plant Terminalia catappa are of great value in cosmetics and therapeutics.
In fact, through the discovery of the inhibitory activity of extracts of the plant Terminalia catappa on the action of enzymes, the invention provides different solutions in the cosmetic and therapeutic fields, especially the dermatological field. As regards the inhibition of phospholipase A2 on the one hand and lipoxygenase on the other, the compositions according to the invention thus have a dual action in the process of formation of the mediators of skin allergy and inflammation, by limiting or blocking this process.
The inhibition of phosphodiesterase (PDE) gives the compositions of the invention a slimming, anti-inflammatory and anti-ageing action. The inhibition of tyrosinase gives them a skin depigmenting effect.
Other advantages of the invention will become apparent from the iption and the Examples which follow.
Thus, according to one of its essential characteristics, the invention relates to cosmetic compositions containing an extract of the plant Terminalia catappa in the presence of a cosmetically acceptable vehicle.
It is essentially the leaves which are found to be of value in the preparation of the extracts of the invention.
The extract is advantageously obtained by maceration of the plant or part of the plant in a solvent or solvent mixture, followed by filtration. The solvent of the solution obtained can be evaporated off, if necessary, to give the dry extract.
The evaporation will preferably be performed under reduced pressure.
The following may be mentioned as solvents which are advantageously used:
water
chlorinated solvents, especially dichloromethane
ethers such as ethyl or diisopropyl ether
acetone
C2 to C8 esters such as ethyl acetate and butyl acetate
C1 to C6 alcohols such as methanol, ethanol and isopropanol
C2 to C6 polyols such as propylene glycol or glycerol.
The plant extract can also be obtained by the so-called supercritical carbon dioxide extraction technique.
In one advantageous embodiment, this composition comprises from 0.001 to 10% by weight and particularly from 0.02 to 1% by weight of dry plant extract, based on the total weight of the final composition.
Furthermore, the experiments carried out by the inventors have clearly shown that not only the extraction yield but also the enzymatic activity of the extract is related to the nature of the solvent used. The attached Examples clearly show the effect of the choice of solvent on the enzymatic activity of the extract.
The compositions according to the invention can be formulated in any form acceptable for their use in cosmetology. In particular, the composition can be in a form appropriate for topical application, specifically in the form of a cream or gel and particularly a cream or gel for the face, hands, bust or body.
According to another aspect, the invention relates to the use of the plant extract as a cosmetic agent, said agent being incorporated in a cosmetic composition as defined above.
This cosmetic agent will be used especially in all applications which are aimed in particular at inhibiting the action of phospholipase A2 and/or lipoxygenase and/or phosphodiesterase and/or tyrosinase.
The compositions according to the invention will also be used to combat the effects of skin ageing, especially by preserving or improving the biomechanical properties of the skin, particularly its elasticity, by delaying the appearance of wrinkles or reducing their depth and by improving the firmness of the skin.
They will also be used for the care of sensitive skin, especially by reducing or eliminating the phenomena of irritation, inflammation or allergy which generally manifest themselves on the skin in the form of red blotches or burning or smarting sensations.
They may also be used to achieve slimming on different parts of the body, particularly the hips. They may also be used for the purpose of reducing or eliminating freckles.
Thus the cosmetic compositions of the invention will be used especially for any cosmetic applications which are aimed at inhibiting the activity of the above-mentioned enzymes.
Thus, according to another aspect, the invention relates to cosmetic compositions intended for skin care and particularly for combating the effects of skin ageing or inflammation phenomena.
They are also found to be of value for their slimming action or their depigmenting action.
As seen previously, it has been possible to correlate the efficacy of the above-described cosmetic compositions with a number of enzymatic activities. The demonstration of these enzymatic activities has also made it possible to consider using the above-defined extracts for the preparation of pharmaceutical compositions, especially dermatological compositions, in which such activities are desired. The experiments carried out by the inventors of the present invention have confirmed the efficacy of these pharmaceutical compositions.
Thus it has been possible to correlate the inhibition of phospholipase A2 and the inhibition of 5xe2x80x2-lipoxygenase with efficacy in the prevention and treatment of inflammation phenomena.
It has been possible to correlate the inhibition of tyrosinase with an action in the local treatment of skin hyperpigmentation.
The inhibition of PDE results in the maintenance of a high intracellular level of cAMP. This leads to a variety of effects concerning the skin, particularly slimming, anti-ageing and anti-inflammatory effects.
Thus, according to another essential characteristic, the invention further relates to the use of an extract of the plant Terminalia catappa for the preparation of a pharmaceutical composition, especially dermatological composition, intended for the treatment of the effects of intrinsic or actinic skin ageing, for the prevention or treatment of the skin manifestations of allergies and inflammations, for the reduction of excess fat or for the treatment of freckles in order to reduce or eliminate them, said extract being incorporated in a pharmaceutically acceptable vehicle.
For these different applications the pharmaceutical composition advantageously has an inhibitory activity on phospholipase A2 and/or lipoxygenase and/or phosphodiesterase and/or tyrosinase.
In one variant the invention relates to the use of an extract of Terminalia catappa for the preparation of a pharmaceutical composition, especially dermatological composition, intended for the treatment and prevention of allergic manifestations, particularly skin allergy.
This type of application is directly associated with inhibition of the lipidic mediators of inflammation.
In all the applications in the pharmaceutical field, especially the dermatological field, the compositions used are preferably compositions for topical application which are intended for application to the skin. Furthermore, the plant extracts used for their preparation are obtained in the same manner as the extracts used in the cosmetic field, from the same parts of the plant, and are introduced into a pharmaceutically acceptable vehicle, especially dermatologically acceptable vehicle, at concentrations of between 0.001% and 10% by weight and particularly of between 0.02% and 1% by weight of dry extract of said plant or part of the plant.
As in the case of the cosmetic applications, the extraction solvent will be chosen according to the type of enzymatic activity which is to be emphasized in the action of the pharmaceutical composition.
According to another variant, the invention relates to a method of treating cellulite, which comprises the application on the part of the body to be treated of a composition comprising an effective amount of an extract of the plant Terminalia catappa. 
In said method, the concentration of the extract and the nature of the solvent used to obtain said extract are advantageously chosen so that the composition has an inhibitory action on at least one of the enzymes selected from the group consisting of phospholipase A2, lipoxygenase and phosphodiesterase.
As for the other applications, the extract is advantageously an extract of leaf and the composition contains advantageously from 0.001% to 10% by weight, and preferably from 0.02% to 1% by weight, of a dry extract of said plant.
The Examples which follow are given purely in order to illustrate the invention.